Image display unit and image forming apparatus including the same

ABSTRACT

An image display unit capable of displaying image data page-wise includes: a scanner portion; a display panel for displaying input image data in preview representation; an input condition determiner that compares the image data successively input through the scanner portion, as to input condition and determines whether there is any change in the image data input condition; and a display controller that, when the input condition determiner determines that the input image data has changed in the input condition, makes control such as to display the image data that was determined to have changed in the input condition and the image data input immediately before the image data in question, together on the display panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of Copending application Ser. No.13/104,692, filed on May 10, 2011, which claims priority under 35 U.S.C.§119(a) on patent application No. 2010-109394 filed in Japan on 11 May2010, all of which are hereby expressly incorporated by reference intothe present application.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates to an image display unit for use in anelectrophotographic image forming apparatus such a copier, printer,facsimile machine or the like and an image forming apparatus includingthe display device, in particular, relating to an image display unitcapable of displaying plural pages of document images in a previewrepresentation as well as to an image forming apparatus including thesame.

(2) Description of the Related Art

A conventional digital multifunctional machine including an imageforming unit, scanner and the like, captures document images as imagedata through the scanner, stores the image data into memory and performsimage recording of the image data based on the stored image data in thememory, in accordance with the conditions the user designates, such asthe number of copies etc., to complete recorded matter.

In this digital multifunctional machine, if the document set on thescanner consists of multiple pages, the bundle of documents is set onthe document tray of a conventionally existing automatic document feederso that the documents are delivered one by one towards the documentreader of the scanner, whereby the image of each document can be read.

In this sequential reading process of documents, some conventionalapparatuses have been adapted to successively compare one document tothe next and ask the operator to confirm continuation of the current jobif any change of documents in image color type (color or monochrome),size, etc., was found by the comparison.

As a conventional technology, there is a disclosure of an image formingapparatus which gives a warning to ask the user to check when the colortype (color or monochrome) of the output image designated by the user isdifferent from the color type (color or monochrome) of the originalimages that have been actually scanned (see Patent Document 1).

As other examples, there is a technology in which if a change indocument characteristics (common properties: document size, colordocument or monochrome document) is observed during scanning multipledocuments, scanning is suspended to inform the user of that fact and askthe user to check the documents (see Patent Document 2). There is stillanother technology in which the document being scanned is determined tobe color or monochrome so as to display a preview of the image of thedocument only when the document is a color one (see Patent Document 3).

Patent Document 1:

Japanese Patent Application Laid-open 2005-189537

Patent Document 2:

Japanese Patent Application Laid-open H07-23147

Patent Document 3:

Japanese Patent Application Laid-open 2009-88693

However, any of the aforementioned prior art technologies are to warnthe user to check the size and/or color type (color or monochrome) ofthe original documents, so that they were not to seek user confirmationafter informing the user of the status of the documents. Therefore, theuser still had to check what state the documents is in.

SUMMARY OF THE INVENTION

The present invention has been devised in view of the above problems, itis therefore an object of the invention to provide an image display unitas well as an image forming apparatus including this, in which, whendata of multiple images is input, the user is able to easily confirm thechange of conditions such as the document size and color type of theinput image data.

The first aspect of the present invention resides in an image displayunit capable of displaying image data page-wise; comprising: an imagedata input portion for receiving input image data; a display portion fordisplaying the image data input from the image data input portion inpreview representation; an input condition determiner that compares theimage data successively input through the image data input portion, asto image data input condition so as to determine whether there is anychange in the image data input condition; and, a display controllerthat, when the input condition determiner determines that the inputimage data has changed in the input condition, makes control such as todisplay the image data that was determined to have changed in the inputcondition and the image data input immediately before the image data inquestion (i.e., the image data located on the previous page), togetheron the display portion.

The second aspect of the present invention is characterized in that thedisplay controller makes control such as to display also the image datainput immediately after the image data (i.e., the image data located onthe next page) that was determined to have changed in the inputcondition, on the display portion.

The third aspect of the invention is characterized in that the inputcondition is document size information.

The fourth aspect of the invention is characterized in that the inputcondition is color type information.

The fifth aspect of the invention resides in an image forming apparatusincluding the image display unit having any one of the above first tofourth aspects.

According to the first aspect of the present invention, since the imagedata that was determined to have changed in the input condition of imagedata and the image data for reference, i.e., the image data inputimmediately before the image data in question(image data located on theprevious page) can be displayed together on the display portion, it ispossible for the user to easily confirm how the input condition of theinput image data has changed.

According to the second aspect of the present invention, the page ofimage data that was determined to have changed is displayed in previewrepresentation by being placed between the images on the pages locatedbefore and after the page in question, hence it is possible to easilyconfirm change of pages.

According to the third aspect of the present invention, it is possibleto easily confirm the status of existence of documents different insize.

According to the fourth aspect of the present invention, for example, bychecking change in color, i.e., monochrome or color, or existence ofboth, it is possible to easily confirm the mixed status of monochromeand color images.

According to the fifth aspect of the present invention, since the imagedata that was determined to have changed in the input condition of imagedata and the image data for reference, or the image data inputimmediately before the image data in question (image data located on theprevious page) can be displayed together on the display portion, it ispossible for the user to easily confirm how the input condition of theinput image data has changed. As a result it is possible to realizeoptimal image output in conformity with document images.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative view showing an overall configuration of animage forming apparatus to which an image display unit according to theembodiment of the present invention is applied;

FIG. 2 is an illustrative view with a block diagram of the image formingapparatus, showing terminal computers being connected to the imageforming apparatus via communication lines;

FIG. 3a is an illustrative view showing an example where a plurality ofdocuments to be scanned by the image forming apparatus include documentshaving document images different in color type;

FIG. 3b is an illustrative view showing a display panel of the imageforming apparatus, on which a preview image of a document having adocument image different in color type from a reference document and apreview image of a document (the reference document) scanned immediatelybefore the document in question, are displayed side by side;

FIG. 3c is an illustrative view showing a display panel of the imageforming apparatus, on which a preview image of a document having adocument image different in color type from a reference document andpreview images of documents that are scanned before and after thedocument in question, are displayed side by side;

FIG. 4a is an illustrative view showing an example where a plurality ofdocuments to be scanned by the image forming apparatus include documentsdifferent in size;

FIG. 4b is an illustrative view showing a display panel of the imageforming apparatus, on which a preview image of a document different insize from a reference document and a preview image of a document (thereference document) scanned immediately before the document in question,are displayed side by side;

FIG. 4c is an illustrative view showing a display panel of the imageforming apparatus, on which a preview image of a document different insize from a reference document and preview images of documents that arescanned before and after the document in question, are displayed side byside;

FIG. 5 is a flowchart for illustrating the processing steps to beimplemented by an image display unit in the image forming apparatus toread a plurality of documents and perform preview display based ondetermined result; and,

FIG. 6 is a flow chart for illustrating the image data processing stepsto be implemented after preview display by an image display unit in theimage forming apparatus.

DETAILED DESCRIPTION OF THE INVENTION

The embodiment of the present invention will hereinafter be described indetail with reference to the accompanying drawings.

FIG. 1 is an illustrative view showing an overall configuration of animage forming apparatus 100 to which an image display unit 1 (FIG. 2)according to the present embodiment of the invention is applied.

As shown in FIG. 1, image forming apparatus 100 includes: a scannerportion (image data input unit) 102 for capturing image data; and anoperational portion 103 having a display panel (display portion) 132 forproviding preview display of image data captured and input by scannerportion 102. Display panel (display portion) 132 can display multiplepreview images of page-wise image data.

Though the present embodiment will be described on the assumption thatthe preview images of multiple document images displayed on displaypanel 132 are given as image data (a bundle of documents given as a job)of documents captured by scanner portion 102 etc., of image formingapparatus 100, the image data taken in by image forming apparatus 100may be given as image data input in communication with a terminalcomputer outside image forming apparatus 100 or image data that isstored in an external memory and loaded through a memory card slot orradio communication.

The apparatus to which image display unit 1 is mounted is not limited toimage forming apparatus 100, but may be an image processing apparatus orelectronic device other than image forming apparatus 100.

This image forming apparatus 100 forms images on recording paper basedon electrophotography.

Further, image forming apparatus 100 includes, as its operation mode,copy mode, facsimile mode (FAX mode), document filing mode (a mode inwhich scanned images are stored in a storage inside the image formingapparatus) and mail mode (a mode in which scanned images are transmittedin the form of a file attached to an e-mail). This image formingapparatus 100 may further have a network printer mode.

To begin with, image forming apparatus 100 will be described.

As shown in FIG. 1, image forming apparatus 100 includes image displayunit 1 (FIG. 2) essentially comprised of scanner portion 102 and anoperational portion 103, a printer portion 104, a paper feeder 106 and apaper discharger (paper output processor) 108.

Scanner portion 102 is mounted on top of the apparatus body and readsimage information from documents.

Operational portion 103 includes a touch-panel display 130 and a displaycontrol portion 140, and is arranged at the top of the apparatus body onthe user' operating side (front side).

Touch panel display 130 is comprised of a display panel 132 of a liquidcrystal panel and the like and a touch panel 134 that is laid overdisplay panel 132 to detect the positions the user presses with fingers.

Display control portion 140 includes an indication lamp 142, a power key144, an energy-save key 146 and a home key 148. Home key 148 is the keythat resets the display content on touch panel display 130 to the homescreen for operational mode selection.

In this way, image forming apparatus 100 has touch panel display 130 asa main control device and also has display control portion 140 thatincludes hardware keys and indication lamp. The keys (power key 144,energy-save key 146 and home key 148) on display control portion 140 aregiven as hardware buttons, in contrast to software buttons formed bytouch panel display 130.

It should be noted that display control portion 140 may be formed oftouch panel display 130 only by replacing the aforementioned hardwarebuttons with software buttons.

In paper discharger 108, a plurality of recording sheets are sorted anddischarged to individual paper output trays 110, and/or each set ofrecording sheets is punched or stapled. For example, when multiplecopies of printed documents are prepared, the printed recording sheetsare sorted and discharged to individual paper output trays 110 so thateach set of recording paper is allotted to different paper output tray110. The thus sorted recording sheets on each paper output tray 110 areindividually punched or stapled into individual printed matter.

Next, the configuration of image forming apparatus 100 will be describedwith reference to a block diagram.

FIG. 2 is an illustrative view with a block diagram of image formingapparatus 100, showing terminal computers PC being connected to theimage forming apparatus 100 via communication lines.

As shown in FIG. 2, image forming apparatus 100 includes scanner portion102, operational portion 103, printer portion 104, a storage 105, paperfeeder 106, a controller 107, paper discharger 108 and a communicator109, each being connected to a bus B.

Image display unit 1 is mainly comprised of scanner portion 102,operational portion 103, storage 105 and controller 107.

Scanner portion 102 is arranged on top of the apparatus body and readsdocument images.

Operational portion 103 receives image forming conditions and a startcommand to the apparatus from the user and gives notice of informationto be notified from the apparatus to the user by means of display panel132.

Storage 105 offers a function as a working memory for temporarilystoring the result of operations and processing by controller 107 and afunction as a frame memory for recording image data. Accordingly,storage 105 records the image data input from external terminalcomputers PC and the like to this apparatus and image data of documentscaptured by scanner portion 102.

Controller 107 controls the operation of image display unit 1 as well asthe mechanisms of the whole apparatus. Controller 107 includes an inputcondition determiner 111 and a display controller 112.

Input condition determiner 111 successively compares multiple pages ofimage data on multiple document images of one job, captured by imagedisplay unit 1, or compares one page with the next, so as to determinewhether there is a change in input conditions (e.g., document size, thecolor type of document image (color or monochrome)) of the documentimages in the job. That is, input condition determiner 111 compares theinput conditions of the image data of two consecutive documents scannedsuccessively by scanner portion 102 to determine whether there is anychange in the input conditions between the image data of the twoconsecutive documents.

In the present embodiment, input condition determiner 111 has a functionof determining whether or not the documents have changed in size basedon the document size information (document size determining function)and a function of determining whether or not the documents have changedin color type (e.g., color or monochrome) based on the color typeinformation on image data (document image color type determiningfunction), as the capabilities to determine the input conditions of theimage data of the documents captured by scanner portion 102.

When a change in input conditions has been detected from the input imagedata, display controller 112 makes control based on the determinedresult from input condition determiner 111 so as to display the imagedata that was determined to have changed in input conditions and theimage data input immediately before the image data in question, togetheron display panel 132.

Further, when a change in input conditions has been detected from theinput image data by input condition determiner 111, display controller112 may make control so as to display the image data in question and theimage data input immediately after the image data in question, togetheron display panel 132. Thus, image display unit 1 is configured.

Printer portion 104 performs image forming based on image data input toimage forming apparatus 100.

Paper feeder 106 pulls out recording paper, one sheet at a time, from astack of recording paper accommodated in the paper cassette (not shown)inside image forming apparatus 100 or the recording paper stacked on amanual feed tray (not shown) outside the apparatus, and delivers thesheet to printer portion 104.

Paper discharger 108 discharges recorded matter that is formed by imageforming apparatus 100.

Communicator 109 is connected to terminal computers PC outside imageforming apparatus 100 to enable communication with the terminalcomputers PC.

Specifically, a public line for exchange of image data is connected tocommunicator 109 of image forming apparatus 100 while a network line isconnected to an unillustrated network interface. This network line maybe connected to external terminal computers PC that use this imageforming portion 100 as a network support printer or may be connected viathe internet to a computer etc. that is designated by a URL (UniformResource Locator). When connected to the Internet in this way, the imageforming apparatus 100 can obtain the necessary information by way of theInternet.

Referring next to the drawings, specific description will be made on thepreview display of document images in image display unit 1 when imageforming apparatus 100 reads documents.

EXAMPLE 1

To begin with, a case where a plurality of documents to be read includedocuments having images different in color (color type) will bedescribed.

FIG. 3a is an illustrative view showing an example where a plurality ofdocuments A1-D1 to be scanned by the image forming apparatus of thepresent embodiment include documents with document images different incolor type.

FIG. 3b is an illustrative view showing display panel 132 of the imageforming apparatus, on which a preview image PC1 of a document C1 havinga document image different in color type from a reference document and apreview image PB1 of a document B1 (the reference document) scannedimmediately before the document C1, are displayed side by side.

FIG. 3c is an illustrative view showing display panel 132 of the imageforming apparatus, on which preview image PC1 of document C1 having adocument image different in color type from the reference document andpreview images PB1 and PD1 of documents (reference documents) B1 and D1that are scanned before and after the document C1, are displayed side byside.

In example 1, multiple documents A1-D1 input into image formingapparatus 100 include color documents A1, B1 and D1 and a monochromedocument C1, as shown in FIG. 3 a.

Image data of documents A1, B1, C1 and D1 are successively read byscanner portion 102 of image display unit 1 and recorded into storage105. Then, based on the recorded image data (document page data), inputcondition determiner 111 successively determines whether there is achange in color type as one of the document image input conditions,between one document and the next.

As a result, input determiner 111 determines that the first two pages,i.e., the document images of documents A1 and B1 are color, the documentimage of document C1 is monochrome, and that the color type of documentC1 is different from that of the previous page or document B1.

Then, based on the determined result from input condition determiner111, display controller 112 displays a preview image PC1 of monochromedocument C1 having a document image different in color type from theother documents and a preview image PB1 of document B1 as the referencefor comparison, on display panel 132, as shown in FIG. 3 b.

At this time, an arrow H1 that indicates preview image PC1 of documentC1 to be checked is displayed on display panel 132, with a message H2,for example “A different document has been detected. Please check it”for promoting the user to confirm the document, arranged near arrow H1.

In the drawings, reference numerals 135 and 136 are “Cancel key” and “OKkey” to allow the user having checked the preview display to input userconfirmation to make reading of the document valid and invalid,respectively.

As described above, in example 1, image display unit 1 displays previewimage PB1 of the second document B1 to be the reference for comparisonon the document image color type as one of document input conditions andpreview image PC1 of the third document C1 to be checked, at the sametime. Accordingly, it is possible for the user to easily compare andconfirm that there is difference in document image color type betweendocument B1 as the reference for comparison and the document image ofdocument C1, among the multiple pages of documents A1, B1, C1 and D1.

As a variation of example 1, the preview display by display controller112 may be given such that in addition to preview image PB1 of documentB1 or the previous page of document C1 to be checked, preview image PD1of the next page, or document D1 may be arranged so as to place thepreview image PC1 to be confirmed between the two. This arrangementenables the user to much more easily confirm how document C1 to bechecked is different from documents B1 and D1 as the reference forcomparison, among the multiple pages of documents A1, B1, C1 and D1.

EXAMPLE 2

Next, a case where a plurality of documents to be read include documentshaving different sizes will be described.

FIG. 4a is an illustrative view showing an example where a plurality ofdocuments A2-D2 to be scanned by the image forming apparatus of thepresent embodiment include a document C2 that is different in size fromthe others.

FIG. 4b is an illustrative view showing display panel 132 of the imageforming apparatus, on which a preview image PC2 of a document C2different in size from a reference document and a preview image PB2 of adocument B2 (the reference document) scanned immediately before thedocument C2, are displayed side by side.

FIG. 4c is an illustrative view showing a display panel 132 of the imageforming apparatus, on which a preview image PC2 of document C2 differentin size from a reference document and preview images PB2 and PD2 ofdocuments B2 and D2 (the reference documents) that are scanned beforeand after the document C2, are displayed side by side.

In example 2, multiple documents A2-D2 input into image formingapparatus 100 include A4-sized documents A2, B2 and D2 and an B5-sizeddocument C2, as shown in FIG. 4 a.

Image data of documents A2, B2, C2 and D2 are successively read byscanner portion 102 of image display unit 1 and recorded into storage105. Then, based on the recorded image data (document page data), inputcondition determiner 111 successively determines whether there is achange in document size as one of the document image input conditions,between one document and the next.

As a result, input determiner 111 determines that the first two pages,i.e., documents A2 and B2 are of A4 size, document C2 is of B5 size, andthat the size of document C2 is different from that of the previous pageor document B2.

Then, based on the determined result from input condition determiner111, display controller 112 displays a preview image PC2 of document C2different in document size from the other documents and a preview imagePB2 of document B2 as the reference for comparison, on display panel132, as shown in FIG. 4 b.

At this time, an arrow H1 that indicates preview image PC2 of documentC2 to be checked is displayed on display panel 132, with a message H2,for example “A different document has been detected. Please check it”for promoting the user to confirm the document, arranged near arrow H1.

As described above, in example 2, image display unit 1 displays previewimage PB2 of the second document B2 to be the reference for comparisonon the document size as one of document input conditions and previewimage PC2 of the third document C2 to be checked, at the same time.Accordingly, it is possible for the user to easily compare and confirmhow document C2 to be checked is different in size from document B2 asthe reference for comparison, among the multiple pages of documents A2,B2, C2 and D2.

As a variation of example 2, the preview display by display controller112 may be given such that in addition to preview image PB2 of documentB2 or the previous page of document C2 to be checked, preview image PD2of the next page, or document D2 may be arranged so as to place thepreview image PC2 to be confirmed between the two. This arrangementenables the user to much more easily confirm how document C2 to bechecked is different in document size from documents B2 and D2 as thereference for comparison, among the multiple pages of documents A2, B2,C2 and D2.

Next, determination of the document type at the time of reading aplurality of documents will be described with reference to a flow chart.

FIG. 5 is a flow chart illustrating the processing steps in imagedisplay unit 1 to read a plurality of documents and perform previewdisplay based on a determined result.

As shown in FIG. 5, when image display unit 1 in image forming apparatus100 starts reading a plurality of documents, scanner portion 102 readsthe documents page-wise (Step S1) and records the image data of thedocuments into storage 105 (Step S2).

Then, it is determined whether or not the read document is the firstpage (Step S3).

At Step S3, if it is determined that the document is the first page, thecontrol goes to Step S4, where it is determined whether or not documentreading has been completed.

If it is determined at Step S4 that document reading has been completed,the processing of reading the documents is ended. If it is determined atStep S4 that document reading has not been completed, the control goesto Step S1 and reading of the next document is carried out.

On the other hand, if it is determined at Step S3 that the document isnot the first page, input condition determiner 111 compares the imagedata of that document with the image data of the document that was readlast (the previous page) (Step S5) so as to determine whether theproperties, i.e., the input conditions (document size, the color type ofdocument image (color or monochrome)) of the current document are thesame as those of the document that was read last (Step S6).

If it is determined at Step S6 that the properties, i.e., the inputconditions (document size, the color type of document image (color ormonochrome), etc.) of that document and the previously read document,are the same, the control returns to Step S4.

On the other hand, if it is determined at Step S6 that the inputconditions of that document and the previously read document aredifferent, the preview of the document image whose input conditions weredetermined to be different is displayed on display panel 132, togetherwith the preview of the previously read document image (the documentimage on the previous page) for comparison (Step S7). With this display,it is possible for the user to easily confirm how the document that wasdetermined to be different in input conditions is dissimilar to theother document.

Then, at Step S8, it is selected whether an OK key 136 is pressed ornot. When OK key 136 is pressed, the control goes to Step S4. If OK key136 is not pressed, it is selected whether a cancel key 135 is pressedor not (Step S9).

As cancel key 135 is pressed, the action of document reading is canceled(Step S10) and the document reading process is ended. If cancel key 135is not pressed, the control returns to Step S8, and the apparatus enterswait mode to wait for next instruction.

In the above way, image forming apparatus 1 reads a plurality ofdocuments and determines whether there is any difference in inputconditions between the read documents and display the result on displaypanel 132. As a result it is possible for the user to easily confirm thedifference in properties between the documents.

Here in the present embodiment, reading of documents are performedreturning to Step Si if document reading has not been completed in StepS4. However, the present invention should not limit the processingsequence of document reading. For example, scanner portion 102 reads aplurality of documents first so that the image data of the read multipledocuments are recorded in storage 105. Thereafter, the image data to becompared may be successively loaded from storage 105 to be used forcomparison.

Next, the image data process that follows the aforementioned documentdetermination, after preview display of image display unit 1 in imageforming apparatus 100 will be described with reference to a flow chart.

FIG. 6 is a flow chart for illustrating the image data processing stepsto be implemented after preview display by image display unit 1.

As shown in FIG. 6, it is determined in image display unit 1, whetherthe image of a document that was determined based on the document inputconditions read by scanner portion 102 is displayed in previewrepresentation on display panel 132 (Step S11).

If it is determined at Step S11 that the image of the document thatneeds confirmation is displayed in preview representation on displaypanel 132, it is selected whether or not OK key 136 is pressed (StepS12).

When OK key 136 is pressed at Step S12, the process of recording imageonto the paper is started (Step S13), and image data processing isended.

If OK key 136 is not pressed at Step S12, it is selected whether or notcancel key 135 is pressed or not (Step S14).

As cancel key 135 is pressed, the action of document reading is canceledwhile the memory is cleared (Step S15), and the image data processing isended. If cancel key 135 is not pressed, the control returns to StepS12, and the apparatus enters wait mode to wait for next instruction.

In this way, it is possible to perform image output after the differencebetween the read documents has been clearly confirmed through imagedisplay unit 1.

According to the present embodiment having the configuration describedheretofore, since image display unit 1 in image forming apparatus 100 isprovided with input condition determiner 111 and display controller 112,when a plurality of documents are scanned (input) successive documentsare compared to each other as to input conditions so that the previewimage of a document to be the reference in comparison for the documentinput conditions and the preview image of a document to be confirmed aredisplayed at once on display panel 132. As a result, it is possible forthe user to easily compare and confirm how the document to be checked isdifferent from the document as reference for comparison.

Further, in the present embodiment, as the capabilities to determine theinput conditions of the image data of the documents captured by scannerportion 102, input condition determiner 111 is provided with a functionof determining whether or not the documents have changed in size basedon the document size information (document size determining function)and a function of determining whether or not the documents have changedin color type (e.g., color or monochrome) based on the color typeinformation on image data (document image color type determiningfunction). Accordingly, it is possible to determine the difference indocument size and in document image color type as document inputconditions.

Further, since display controller 112 makes control based on thedetermined result from input condition determiner 111 so that the imagedata that was determined to have changed in input conditions and theimage data input immediately before the image data in question aredisplayed together on display panel 132, it is possible for the user toeasily compare and confirm how the document different in inputconditions differs from the other.

Further, when input condition determiner 111 determines that the imagedata has changed in input conditions, display controller 112 functionsto display the image data in question and the image data inputimmediately after the image data in question, together on display panel132, it is possible to make the user compare and clearly confirm how thedocument different in input conditions differs from the others.

The above embodiment was described taking an example in which imagedisplay unit 1 is applied to image forming apparatus 100 shown inFIG. 1. However, as long as it is an image forming apparatus that canpresent document images in preview representation on the display panelor the like before printing, the invention can be developed to any otherimage forming apparatus and the like, not limited to the image formingapparatus and copier having the configuration described above.

Having described heretofore, the present invention is not limited to theabove embodiment, various changes can be made within the scope of theappended claims. That is, it is apparent that various kinds ofvariations and modified examples will occur to those skilled in the artwithin the scope of the appended claims. That is, any embodied modeobtained by combination of technical means modified as appropriatewithout departing from the spirit and scope of the present inventionshould be included in the technical art of the present invention.

What is claimed is:
 1. An image display unit capable of displaying imagedata page-wise, comprising: a storage storing a plurality of successivepages of page-wise image data; a display panel displaying the image dataread from the storage in preview representation; and a controllerperforming a determination process that determines whether there is anychange in a second input condition of a determination image data as asecond image data to be determined in comparison with a first inputcondition of a reference image data as a first image data, wherein thedetermination image data is an image data subsequently storedimmediately after the reference image data into the storage, and whenthe controller determines that there is a change in the second inputcondition compared with the first input condition, the controllercontrols the display panel to display, in parallel, the reference imagedata and the determination image data side-by-side.
 2. The image displayunit according to claim 1, wherein the controller repeats thedetermination process, after completion of a previous determinationprocess, by replacing the first image data as the reference image datawith a second image data as the determination image data and byreplacing the second image data as the determination image data with athird image data inputted.
 3. The image display unit according to claim1, wherein when the controller determines that there is the change inthe second input condition compared with the first input condition, thefact that there is the change is warned on the display panel.
 4. Theimage display unit according to claim 1, wherein the controller controlsthe display panel to display also the third image data input immediatelyafter the image data that was determined to have changed in the inputcondition.
 5. The image display unit according to claim 4, wherein thefirst input condition is one page size of the first image data, and thesecond input condition is one page size of the second image data.
 6. Theimage display unit according to claim 4, wherein the first inputcondition is color type information used in the first image data, andthe second input condition is color type information used in the secondimage data.
 7. The image display unit according to claim 1, wherein thefirst input condition is one page size of the first image data, and thesecond input condition is one page size of the second image data.
 8. Theimage display unit according to claim 1, wherein the first inputcondition is color type information used in the first image data, andthe second input condition is page size of the second image data.
 9. Animage forming apparatus including the image display unit according toclaim 1.